Acoustic measuring systems and distance measuring systems are utilized in a variety of applications. For example, acoustic measuring systems are utilized to measure obstacle distance in applications ranging from automotive systems to fossil discovery. Acoustic measuring systems generally operate by first transmitting a pulse of acoustic energy, creating a sound wave. Then a measurement of the time of flight of the sound wave is recorded. The time of flight, which is the time from transmission of the sound wave until a reflection of the sound wave is received, determines the distance of the obstacle. Automotive applications that utilize acoustic measuring systems require reliable detection of the presence of an obstacle. Currently, the reliable detection of obstacles may be opposed by obstacles positioned in the blind spot of a detection device, as well as extreme electrical noise causing false obstacle detection.
Acoustic measuring systems often utilize acoustic transducers both to transmit the generated sound wave, and to receive the reflected signal, or echo signal. These systems may have a certain distance within which an obstacle cannot be detected. A lower minimal distance required for detection of an obstacle results in more accurately detected objects, thereby resulting in higher automotive safety. Current acoustic measuring systems are also highly susceptible to extreme electrical noise, which is one factor in creating false object detection signals. As electromagnetic compatibility (EMC) requirements change, higher levels of electrical noise in allowed frequencies are unavoidable and may interrupt accurate acoustic distance detection. False object detection or missed object detection could be detrimental in automotive and other acoustic measuring applications. Therefore, avoiding false-positive object detection and false-negative object detection is important to insure proper acoustic measuring system functionality and reliability.
The use of the same reference symbols in different drawings indicates similar or identical items. Unless otherwise noted, the word “coupled” and its associated verb forms include both direct connection and indirect electrical connection by means known in the art, and unless otherwise noted any description of direct connection implies alternate embodiments using suitable forms of indirect electrical connection as well.